Leading Republicans, Democrats reject Trump's Obama wiretap assertion

The top Republican in Congress, House of Representatives Speaker Paul Ryan, added his voice to a growing chorus of lawmakers saying there was no sign of a wiretap.

In a testy briefing with reporters, White House spokesman Sean Spicer forcefully defended the president, citing news reports of intelligence collection on possible contacts between Trump associates and Russia in the presidential campaign.

U.S. President Donald Trump walks from Marine One as he returns to the White House in Washington. REUTERS/Joshua Roberts

"There is no question that there were surveillance techniques used throughout this," Spicer said.

The Republican president, without providing evidence, has accused his predecessor, Democrat Barack Obama, of wiretapping him near the end of the campaign. An Obama spokesman said that was "simply false."

"Based on the information available to us, we see no indications that Trump Tower was the subject of surveillance by any element of the United States government either before or after Election Day 2016," Richard Burr, the Republican chairman of the Senate Intelligence Committee, and Senator Mark Warner, the committee's Democratic vice chairman, said in a statement.

Ryan also said there was no evidence of surveillance.

"The point is, the intelligence committees in their continuing, widening, ongoing investigation of all things Russia, got to the bottom - at least so far - with respect to our intelligence community that - that no such wiretap existed," the House speaker told reporters.